We report an improved synthesis of 1,1′-diaminoferrocene, employing the reduction of 1,1′diazidoferrocene with H 2 -Pd/C, along with extensive characterization data for both compounds. Diaminoferrocene undergoes a reversible 1eoxidation in CH 3 CN at a potential of -602 mV vs Fc 0/+ , one of the most negative redox potentials for a ferrocene derivative. The chemical reversibility of this process was confirmed by isolation of the stable, 17-electron [Fc(NH 2 ) 2 ] + cation as PF 6 -, OTf -, and TCNEsalts. In the solid state, diaminoferrocene exists in two conformations: one with the NH 2 groups eclipsed, and the other with the NH 2 groups offset by one-fifth turn around the Cp-Fe-Cp axis. Diazidoferrocene, on the other hand, exhibits only the fully eclipsed conformation in the solid state. The Fe-Cp(centroid) vectors in the diazidoferrocene molecules are roughly aligned with the crystallographic c-axis, and the molecules form layers perpendicular to this axis. The compound is thermally unstable at elevated temperatures, and rapid heating above its melting point results in explosion.

Silylation of 1,1′-diaminoferrocene afforded 1,1′-Fc(NHSiMe 3 ) 2 (LH 2 ) as red air-sensitive crystals. Reaction with M(CH 2 Ph) 4 (M ) Ti, Zr) afforded the corresponding LM(CH 2 Ph) 2 (M ) Zr; Ti), where the Fc(NSiMe 3 ) 2 2group serves as a diamide ligand. Alternatively, the magnesium salt LMg(THF) 2 was reacted with TiCl 4 (THF) 2 to give LTiCl 2 as purple airsensitive crystals. Methylation of the latter with MeLi affords LTiMe 2 .

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